Slide-valve



(No Mode.) 2 Sheets-Sheet D. OB. LADD.

SLIDE VALVE.

No. 377,078. Patgnted Jan.. 31, 1888.

(No Model.) 2 Sheets-Sheet 2.

D. OB. LADD. l

SLIDE VALVE.

No. 377,078. Patented Jam.v 81, 1888.

Y stroke.

NTTED STATES PATENT OFFICE.

DENNIS OB. LADD, OF CHICAGO, ILLINOIS'.

SLI DE'.-VALVE.

SPECIFICATION forming part of Letters Patent No. 377,078, dated January 31, 1888.

(No model.)

lb aZZ whom t may concern:

Beit known that I, DENNrs OB. LADD, of Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Slide-Valves, of which the following is a description, reference being had to the accompanying drawings, forming a part of this specification, in which- Figure l is a face view of said valve and steanrchest, the cap being removed from the latter. Fig. 2 is a transverse sectional view of the same and a part of the cylinder upon the line x w, Fig. l, viewed in the direction of the arrow there shown. Fig. 3 is a transverse sectional view of the valve upon the line yy, Fig. 1, viewed in the direction of the arrow Y. Fig. 4 is atransverse sectional view of the valve and steamehest in connection with the cylinder and piston,as viewed in the direction of the arrow Y2, the admission-port being fully open and the piston at the beginning of thc stroke. Fig. 5 is a like view showing the position of the valve at one-quarter stroke, and Fig. 6 is a like view showing the position at One-half stroke.

Like letters of reference indicate like parts in the different gures.

The object of my invention is to so construct a slide-valve as to utilize the expansion of the steam as well as the compression in balancing the valve and helping to actuate it, while at the same time a high initial pressure may be given to the piston at the beginning ofthe l accomplish said objectsubstantially in the manner hereinafter shown7 described,

,and claimed.

A in the drawings represents the engine-cylinder; B, the steam-chest, and C the main slidevalve, which consists of a hollow box or shell having openings c c, Figs. 4, 5', and 6, upon its front and rear sides, respectively. Said valve is reciprocated by means of a loose yoke, D, to which the valve-rod E is attached, substantially as shown. The lower part of the valve C, or valve proper, is provided with double ports c c2 c3 0*, arranged to communicate with the steamways a a. Said valve is also provided with an exhaust-port, c5, in communica` tion with an exhaust-way, ci. A removable cap, C', is made to form a part of the valve C, and between said cap and the part of the valve which contains said ports I placca loose supplemental valve, F, which is preferably provided with anges ff, Figs. 2 and 3, adapted to slide within grooves formed in the ends of the main valve C. An arched chamber, F', is formed beneath the middle of said supplemental valve; and chambers F2 F3, parallel with the admis sionports,are also formed upon the respective sides thereof and adjusted to communicate with said ports, respectively, in the manner and for the purposes hereinafter stated, as the valve is actuated. Said chambers are separated from each other by means of a web or partition, f. A disk, G, provided with a flange, g, is loosely mounted in a bearing in the cap C'. H is an arm rigidly attached to said disk, the end of which is connected by a link, H', to a lug, h, upon the side ofthe steam-chest.

J, Figs. 1 and 2, is a slot in the disk, in which is looselyinserted a bushing, J Apin, fi, is rigidly attached to thetop of the supplemental valve and passed through a perforation in the bushing J. vUpon actuating the main valve the disk G acts as an eccentric and reciprocates the supplemental valve within the main valve at a rate of speed greater in proportion to the eccentricity of the pin f".

lt will be observed upon reference to Fig. el, which indicates the relative positions ofthe parts at the beginning of the piston-stroke, that the supplemental valve is so situated with reference to the steam-ports as to permit the exhaust steam to enter the chamber F2, while at the same time it presses upwardly against the chamber F. As the piston advances, the live steam enters said chamber F2, (see Fig. 6,) and, expanding, tends to resist the pressure upon the opposite side and to aid in pushing the valve forward. At the same time it is evident that the compression is acting through the port ctwithinthe chamber F". Thus at no appreciable time is the valve free from a balancing force, the secondary or auxiliary ports c3 c* permitting the steam to have continuous access to said chamber, while the eX- haust through said ports is permitted to commence at an earlier stage than it would in the absence of said ports.

Having thus described my invention, I claim@ l. The combination, with the steamways of a steam-cylinder, of a main slide-valve having a central exhaust-port and double ports near 2 errore' ing said supplemental valve at a higher rate4 of speed than said main valve, substantially as shown and deseribed.

2. Amain slide-valve provided with double ports at or near its respective ends, in combination with a supplemental valve for opening and closing said ports, means, as an eccentric having a linlrconnection with the steam-chest, for imparting av higher relative speed to said supplemental valve, an'exhaust-cavty beneath t-he latter, and separate chambers upon the respective sides of said exhaustcavity, said chambers being adjusted to communicate in turn4 with said double ports and the exhaustport of the main valve, substantially as shown and described.

3. The combination, with the steamways of a cylinder, of a main slide-valve arranged to admit steam to said ways atits respective ends, ports c 0205 o4, a main exhaust-port, a supplemental valve arranged to open and close said double ports at the respective ends of the valve, an exhaust-cavity, chambers li2 F3, and

means for imparting a quicker throw to said supplemental valve than to the main valve,

substantially as shown and described.

4. The combination, With a cylinder having suitable steamways, of a main slide-valve having admission-ports near its respective ends inaddition to a main and auxiliary exhaustsports, a supplemental valve provided with an exhaust-chamber and having separate chambers upon the respective sides of said exhaustchamber, said supplemental chambers being adapted to be brought coincident with said admission and exhaust ports,and means for reciprocating said supplemental valve with each stroke of the main valve, but with a quicker movement, substantially as shown and described.

5. Thecombination ofthe slide-valveC, having an exhaust-port and double ports near its ends, with a supplemental valve, chambered as described, and means, as the eccentric G, connected by an arm-and-link connection with the steam-chest, and pinfz, foi-actuating said supplemental valve, substantially as shown and described.

' DENNIS OB. LADD.

Witnesses:

D. H. FLETCHER, J. B. HALPENNY. 

